1. Field of the invention
The present invention concerns a paying out/winding in device for eliminating torsion in a line in a rotary connection between a fixed member and a mobile member to which respective ends of the connection are fixed. Descriotion of the prior art
There is already known in the prior art, in particular from FR-A-2 188 593, a paying out/winding in device comprising coaxial fixed and mobile spools designed to be respectively fastened to the fixed member and the mobile member of the rotary an arm adapted to rotate about the common axis of said fixed and mobile spools and carrying at its free end a satellite pulley which, when rotating more slowly than the mobile spool, transfers the line from the mobile spool, to the fixed spool or vice-versa, and drive means for rotating the arm comprising at least one sliding coupling having a primary member coupled to the mobile spool by a first freewheel mechanism and to the fixed spool by a second freewheel mechanism, and whose secondary member is fastened to the arm.
A serious disadvantage of this known device is that the axis of the satellite pulley is perpendicular to the axis of the spools. As a result, if it is used with flat optical fiber or other type cables, for example, substantial torsion is applied to the cable, especially between the spools and the satellite pulley, because of the marked change of direction of said cable.
Also, in this known device the sliding couplings are friction clutches. This type of clutch is disadvantageous in that it is not able to transmit to the arm a constant driving or braking torque. In particular, jerks occur on starting and stopping because of the changeover from static mode to dynamic mode friction or vice-versa and these are extremely hazardous in the case of cables such as optical fiber cables.